Climate and environment
Archaeological sites containing plant and beetle remains more than half a million years old are extremely rare. At Happisburgh, the long-term preservation of these remains was made possible by rapid burial and waterlogging, which has slowed decay.
Several plant and animal species have distributional limits that are governed primarily by temperature and these are key to reconstructing the climate conditions and the vegetation during the period of human occupation at Happisburgh.
Reconstructing the climate
Among the most fragile of the fossils preserved are the exo-skeletons of insects, including numerous species of beetle. Beetles in particular are extremely useful for reconstructing past climates because the climatic tolerances of many of the species are known. This information can be used to estimate average temperatures of the coldest and warmest months. The results suggest that summer temperatures (between 16 and 18 °C) were similar or possibly slightly warmer than southern Britain today, but mean winter temperatures (between 0 and -3 °C) may have been as much as 6 °C lower than today. A similar climatic regime is experienced by areas of southern Scandinavia today. The Happisburgh beetle assemblage also includes rare non-British species that have a southern distribution. These beetles do not necessarily indicate warmer temperatures as their distributions are restricted to the cold mountain peaks of the Pyrenees.
Reconstructing the vegetation
The vegetation also provides important climatic information. The pollen record from the Happisburgh channel shows that the sediments were deposited during an interglacial characterised by warm temperate environments (dominant broad-leaved deciduous woodland) during the interglacial peak, followed by cooling indicated by a shift to conifer-dominated woodland. The artefacts are associated with the shift to conifer-dominated woodland and an earlier heathland episode.